The Zona Reaction of Hamster and Mouse Eggs: Production in Vitro by a Trypsin-Like Protease From Cortical Granules

Abstract

Summary. The

Oviduct function in pigs, with particular reference to the pathological condition of polyspermy

“…I also wish to thank Mrs. telline space (Verhage and Fazleabas, 19901, facilitates Frances Anderson for kindly typing the manuscript. either a more svnchronous exocvtosis of the cortical ACKNOWLEDGMENTS is that a glYcoProtein On the Agricultural Research Council (UK), for which grateful granule contents or expedites andaugments physiological responses of the zona substance to cortical granule material (Barros and Yanagimachi, 1971;Gwatkin et al, 1973), leading more efficiently to establishment of a functional block to polyspermy. Irrespective of which of these or indeed other possibilities, such as an influence on the sperm plasmalemma to stabilise and reduce the numbers becoming capacitated simultaneously, ultimately turns out to be correct, interpretation of the egg transplantation studies described earlier in this review may also need to take into account these putative influences of oviduct fluid glycoproteins rather than focussing simply on the number of competent sperm cells available at the site of fertilisation.…”

Membrane Fusion Events in Fertilization

“…By contrast, electrical stimulation of hamster eggs with a square-wave pulse of 150 V for 1 msec was said to be highly effective in eliciting the reaction (Gwatkin et al, 1973;Gwatkin & Williams, 1974). …”

“…Gwatkin, Williams, Hartmann & Kniazuk (1973) offered evidence that the hamster cortical granules released a trypsin-like enzyme, finding that trypsin inhibitors prevented the consequences of cortical granule breakdown. More recently, Gwatkin (1974) reported that the cortical granule protease closely resembles acrosin; taken in conjunction with the derivation of acrosome and cortical granules from Golgi complexes, the observation points to a much closer homology between the two gamete organ¬ dies than had previously been appreciated.…”

Heat Sensitivity of the Cortical Granule Protease From Hamster Eggs

“…Once discharged into the medium, however, it is extremely heat sensitive, undergoing inactivation even at 37\s=deg\C. Thus, body temperature would be expected to prevent the zona reaction of one egg from rendering neighbouring eggs infertile.Previous studies (Gwatkin, Williams, Hartmann & Kniazuk, 1973) showed that the zona reaction of the hamster ovum is produced by a cortical granule protease, which inactivates the species-specific receptor-for-spermatozoa located in the zona pellucida. This receptor was earlier shown to be sensitive to low concentrations of pancreatic trypsin (Hartmann & Gwatkin, 1971 …”

“…Previous studies (Gwatkin, Williams, Hartmann & Kniazuk, 1973) showed that the zona reaction of the hamster ovum is produced by a cortical granule protease, which inactivates the species-specific receptor-for-spermatozoa located in the zona pellucida. This receptor was earlier shown to be sensitive to low concentrations of pancreatic trypsin (Hartmann & Gwatkin, 1971).…”